BT-Spannschloss® – BT turnbuckle®

Technologien und Beratung für den Betonbau - B.T. innovation

Connection technology for the permanent connection of precast concrete elements

Wand mit BT-Spannschloss

What does this product have to offer?

With the BT-Spannschloss®, precast concrete parts can be connected without any other additional materials or aids. (Connecting concrete)
The joint is immediately fully loadable without consideration of curing times and thus creates a considerable time and cost saving compared to other known systems.

Your advantages

Product details

The BT-Spannschloss® enables rational and precise assemblies as well as permanent connections of precast concrete elements. By using the BT turnbuckle and corresponding fasteners, precast elements can be joined together without a mineral grout. This eliminates curing times or downtimes due to low temperatures. The connection with the BT-Spannschloss® can be fully loaded immediately. You can watch the application of the BT-Spannschloss® in the product video.

The general technical approval (Z-14.4-599) and the European Technical Assessment (ETA 19/0013) certify the reliability of the product. The BT turnbuckle® is offered in three sizes – M12, M16 and M20 – and is available in galvanised or stainless steel. On 12 March 2021, BT-Spannschloss® M12, M16 and M20 received the CE marking for use in the European Economic Area (EEA).

360° view of the BT-Spannschloss® – M20

(Use the mouse to rotate the object or click here to open a new window).

Areas of application for BT-Spannschloss®

The BT clamping system can be used rationally and universally in a wide range of applications. For example, in the assembly and connection of angular supports and shaft elements in road construction and civil engineering, in construction measures in coastal protection areas, in ceiling and wall connections in residential and social construction and many other structural connections of precast concrete elements.

Note: The load capacity of the tensioning system depends largely on the type of anchor used. Several types of authorised anchor systems can be used according to the application requirements (please refer to the manufacturer’s data). In general, the load capacity of the turnbuckle is many times higher than that of the anchor systems.

BT-Spannschloss® - recess body

There is a matching recess body for each of the three sizes of the BT-Spannschloss®. The standard version of the recess body is made of polyethylene and has sloping sides for better stripping. It is possible to adapt the recess bodies in dimension or shape according to customer requirements.

The PE recess bodies are particularly robust and can therefore be reused many times. They enable a particularly stable positioning of the anchors and also ensure sufficient concrete cover for anchors and BT-Spannschloss®. For faster and more reliable application, the recess bodies can be equipped with magnets. Depending on the installation situation, however, it is also possible to screw or drill into the recess bodies if necessary.


Questions and answers about the product

1. what are the connection situations?

Basically, the BT turnbuckle can be used as a butt joint, corner joint and three-point connection. Depending on the application, the type of recess in the precast concrete plant differs. Whereas the recess in the corner joint must be located as a whole in one element, the recess body can also be divided into two elements in the butt joint. For further information on the correct use of recess bodies, please contact your BT representative.

2. what does the system consist of?

The BT turnbuckle® is available in three different sizes depending on your needs: M12, M16 and M20. In both the galvanised and stainless steel versions, the connection system consists of three essential components: the BT-Spannschloss®, the washers and the hexagon bolts.

3. what tolerances can the BT-Spannschloss® compensate for?

Dimensional tolerances of the joints and involved components are tolerable as long as the tensile force transfer of the anchor is guaranteed and the minimum screw-in depth of the screws is achieved.

4. how does the formation of the correct joint width work?

The joint widths can be varied by using different screws. The correct bolt combination can enable a regulation-compliant installation of the BT turnbuckle, even with component tolerances. However, the minimum required and the maximum possible screw-in depth must always be observed.

5. is the BT-Spannschloss® corrosion protected and fire protection compliant?

Yes, the BT-Spannschloss® is protected against corrosion when installed in accordance with the approval. If, in addition, particularly strong chemical stresses occur, the stainless steel version can be used. Our BT-Spannschloss® also fulfils various fire protection requirements. Detailed results of fire protection tests carried out can be obtained from your BT contact.

Other products from the category Connection technology


GFRP spacer bar


ThermoPin® – Composite anchor

Spannschloss Produktbild

BT-Spannschloss® – BT turnbuckle®

Scroll to Top